A major goal of the neuroscience community is to develop treatment strategies that will slow or forestall the progression of chronic neurodegenerative diseases. Parkinson's disease (PD) is one of the most common adult neurodegenerative disorders, affecting over 1 million people in North America and the European Union. As a first step in identifying such therapies, the NINDS Exploratory Trials in Parkinson's disease (NET-PD) network successfully completed futility studies, which identified creatine as a potential agent to slow clinical decline in PD. The NET-PD network is now conducting a large, long-term. Phase 3 trial (known as LS1) comparing creatine to placebo. The Movement Disorders Program at the Medical University of South Carolina (MUSC) was awarded the U10 NS053372 award as a Parkinson's Disease Neuroprotection Clinical Trial Center in 2006 and is one of the current sites for the LS1 study with 36 study local study participants. With this application, MUSC seeks out funding to continue the LS1 study for 3 additional years, and to continue cooperating with the other NET-PD centers (including the Coordination and Statistical Centers) towards the goal of successfully completing the current trials.